That Mossberg 500 of which you speak is a great deal at the present $269, if it goes on sale, I'd go down and buy it myself! Seriously, the 'combo' model that you reference is the Mossberg solution to a HD shotgun coupled with an 'occasional' hunter or trap/skeet shooter. It's as close as they sell to a do-it-all shotgun when the barrel length and choke options are the limitation of having a long HD gun. IMO, the 5-shot magazine (+1 chamber) of the conventional M500's is nothing to sneeze at, since you'll be adding a mag limiter if you hunt, anyway.
My personal solution to the 'do-it-all' problem was a M500, 5-shot, ghost-rings, choate forearm and SpeedFeed III (standard-type) magazine stock with factory 18.5" cylinder bore barrel. About 6 months ago, I found a guy willing to part with a 24" screw-in choke barrel w/ IC, M and Full chokes for $90 that was a good price and is now my 'hunting' combination for upland game where I live.
The 'combo' of the barrels being swapped out based on use is a very utilitarian solution and gives you the added performance of a long barrel and chokes for gun games or upland hunting without losing the utility of a short barrel for HD use. If you like wood, so much the better...
Mossberg is a quality manufacturer, as are the others, and I'm sure you'll be well-served by any of those named. Now, whereabouts was that store you mentioned??? (j/k)